... delivery & top quality 4) Professional service. Features of our rubber O-ring: · Working temperature: -100 to +300 degrees;· Hardness: ... tensile Strength, Wear and tear resistance, Durable;· UL certification;· Rubber Material: NBR, HNBR, XNBR, EPDM, CR, NR, SBR ... the following features of all kinds rubber material, please choose the suitable one for your items, thanks. Material NameHardnessWorking ...